Closable well in hull of deep ocean mining vessel

ABSTRACT

A surface vessel for deep ocean mining having a large opening through the center of the hull which can be closed from the sea by means of large movable gates. Mining machinery can be stowed in this center well and, with the gates closed, the well can be pumped dry, providing a maintenance area. With the gates open and the well flooded, the mining machinery can be lowered to, or raised from, the floor of the ocean. The well is closed by two gates, which move fore and aft relative to each other and slide in guides mounted beneath the hull of the ship. The gates are provided with segmented compartments into which air can be pumped to increase their buoyancy. The buoyant gates press upwardly against the bottom of the hull to seal off the well area from the sea. To open the gates, the seal is broken by bleeding the air and allowing sea water to flood the segmented compartments.

United States Patent Graham et al.

1 CLOSABLE WELL IN HULL OF DEEP OCEAN MINING vEssEL [73] Assignee:Global Marine Inc., Los Angeles,

Calif.

Filed: June 13, 1974 Appl. No.: 479,097

[56] References Cited UNITED STATES PATENTS 6/1913 Reid 114/36 12/1958Hoitt et a1 114/173 FOREIGN PATENTS OR APPLICATIONS 1,510.126 France114/05 D Nov. 11, 1975 Primary Eraminer-Trygve M. Blix AssistantE.raminer$herman D. Basinger Attorney. Agent, or FirmChristie, Parker &Hale [5 7 ABSTRACT A surface vessel for deep ocean mining having a largeopening through the center of the hull which can be closed from the seaby means of large movable gates. Mining machinery can be stowed in thiscenter well and, with the gates closed, the well can be pumped dry,providing a maintenance area. With the gates open and the well flooded,the mining machinery can be lowered to, or raised from, the floor of theocean. The well is closed by two gates, which move fore and aft relativeto each other and slide in guides mounted beneath the hull of the ship.The gates are provided with segmented compartments into which air can bepumped to increase their buoyancy. The buoyant gates press upwardlyagainst the bottom of the hull to seal off the well area from the sea.To open the gates, the seal is broken by bleeding the air and allowingsea water to flood the segmented compartments.

7 Claims, 4 Drawing Figures US. Patent Nov. 11, 1975 Sheet 1 of33,918,380

& ww N w in; E M u U.S. Patent Nov. 11, 1975 Sheet 3 013 CLOSABLE WELLIN HULL OF DEEP OCEAN MINING VESSEL FIELD OF THE INVENTION Thisinvention relates to a deep ocean mining ship, and more particularly, toa mining ship havinga docking well which is opened and closed to the seaby gates.

BACKGROUND OF THE INVENTION In copending application Ser. No. 479,091,filed June 13, 1974, entitled Apparatus for Raising and Lowering PipeString From a Floating Vessel, filed in the names of Robert CurtisCrooke and Abraham Person,

as inventors, and assigned to the same assignee as the presentinvention, there is described a deep ocean mining vessel in which heavymining equipment can be raised and lowered between the vessel and theocean floor. Because the subsea mining equipment is heavy andbulky, itis desirable to raise and lower the equipment through the center of thevessel. Unlike some oil drill ships, which provide a small openingextending through the center of the vessel to permit drill pipe to beraised and lowered from the surface vessel, the deep ocean mining vesselrequires a well sufficiently large to store the mining machinery withinthe ship while in transit to various mining locations and port.

SUMMARY OF THE INVENTION The present invention is directed to a surfacevessel having a large center well, the bottom of which can be opened andclosed by a pair of sliding gates movable horizontally along thebottom-of the vessel. The gates are provided with water-tightcompartments from which air or water can be added or removed to controlthe buoyancy of the gates. When closed, the gates seal off the well fromthe sea, permitting the docking well to be pumped dry. By pumping airinto the gate compartments, the gates are forced more tightly againstthe bottom of the vessel to form an efficient positive seal.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding ofthe invention, reference should be made to the accompanying drawings,wherein: I

FIG. 1 is a side elevational view of a ship incorporating the featuresof the present invention;

FIG. 2 is a fragmentary sectional view of the docking well;

FIG. 3 is a plan view of the gates and associated guide structure; and

FIG. 4 is a fragmentary sectional view showing details of the gate driveand support mechanism with the gate partially open.

DETAILED DESCRIPTION Referring to FIG. 1, the numeral indicates thegeneral outline of the hull of a ship designed for deep ocean mining,such as described in detail in the aboveidentified copendingapplication. The midships portion of the vessel has a large open well 12which extends vertically through the hull 16 from the main deck 14 andthrough the bottom of the vessel. The well 12 extends fore and aftapproximately a third of the total length of the vessel and isessentially rectangular in shape enclosed by vertical sidewalls l7, andfront and rear vertical endwalls 19 and 21, and bottom gates 20 and 22.The top of the well is open.

Although not specifically shown in the drawings, heavy lift equipmentfor raising and lowering mining machinery or other equipment from thewell 12 to the bottom of the ocean spans the top of the well between theportions of the top deck 14 on either side of the well 12, such asdescribed in the aboveidentified copending application. The mining orother equipment (not shown) is docked inside the well while the ship isin transit.

The bottom of the well 12 is provided with a pair of gates 20 and 22which close the well opening at the bottom of the ship. The respectivegates move horizontally in a fore and aft direction along the bottom ofthe ship. To this end, the gates 20 and 22 are movable along a pair ofparallel gate guide members 24 and 26 extending in a fore and aftdirection and secured to the bottom of the vessel on either side of thewell opening. As best seen in FIG. 4, each guide member includes avertical guide surface 30 extending downwardly from the bottom 16 of thevessel to a horizontal guide surface 32 which projects inwardly from thesurface 30. Each of the gates 20 and 22 include parallel flat sideplates 34. To each plate is secured projecting guide and sealingassembly 36. The guide assembly 36 includes a boxshaped girder 37extending the length of the gate side plates. A plurality of rollers 38are journaled within the box girder for rotation about a horizontalaxis, the rollers 38 projecting outside the girder are in rollingcontact with the horizontal surface 32 of the guide members 24 and 26.In addition, a plurality of rollers 40 are journaled in the box girder37 of the guide assembly 36 for rotation about a vertical axis, therollers 40 having rolling contact with the vertical surfaces 30 of theguide members 24 and 26.

The gates 20 and 22 are constructed of multiple transverse bulkheads 42covered with flat top plates 44, which form the bottom of the well withthe two gates closed and bottom plates 46 which are exposed to the sea.As shown by the cross section of FIG. 4, the bottom plate is angledupwards slightly from the middle of the plate to the side plate 34. Thislends stability both to the movable gate and to the vessel itself. Asshown in FIG. 3, the bulkheads 42 are braced by fore and aft spacers 47to form a rectangular cellar structure. The interior of the gates aredivided into separate watertight compartments for ballast, nine suchcompartments per gate being shown. Any combination of compartments canbe opened to the sea through the bottom plates 46. The buoyancy of thegates is controlled by displacing the sea water from selected ballastcompartments with compressed air. To increase buoyancy, air is pumpedinto the gate compartments. To decrease the buoyancy, the air isreleased, allowing the sea water to re-enter the compartments. To thisend several air valves 50 are mounted below the top plate 44, the valves50 being connected to respective compartments within the gates bysuitable pipe connections 51. These valves can be operated from the maindeck to control the flow of compressed air into or bleed air out of thegate compartments.

To open and close the gates, each gate is provided with two gear racks52 and 54 extending down the center for the full length of the gate. Asshown in FIG. 4, the racks are recessed in the top plates 44 of thegates so as not to interfere with the movement of the gates outwardlybeneath the bottom of the ship. The drive mechanism for opening andclosing each of the gates includes a pair of gears 56 which engages theracks 52 and 54. Each of the gears 56 rotates on a drive shaft 58. Sincethe gear and rack are exposed to the sea water when the gates areopened, the drive gear 56 is enclosed within a water-tight compartment60. The shaft 58 extends through the wall of the compartment 60 througha sealed packing gland and bearing 62. Thus the sea water is confined tothe interior of the compartment 60. The shaft 58 is journaled at itsother end in a bearing block 64. Rotation is imparted to the gear 56 bya suitable hydraulic motor 66 through a gear reduction drive 68. Theoutput of the gear drive 68 is coupled through a chain drive 70 to asprocket 72 on the shaft 58. Four such drive assemblies are provided,one for each rack on the respective gates and 22.

When moved to their closed positions, the gates 20 and 22 engage stops74 and 76 projecting from the vertical surface of respective guidemembers 24 and 26. The stops engage recesses 78 and 80 in the gate 20,and 82 and 84 in the gate 22. The abutting end of the gate 20 isprovided with a seal 86 (see FIG. 2) which provides a watertightinterface when it engages the surface of the abutting end of the gate 22with the gates closed. In addition, a flexible seal is secured aroundthe upper perimeter of the gates, as indicated at 88 and 90,respectively. As seen in FIG. 4, the sealing members 88 and 90 projectabove the top plate 44 of the gate toward the bottom of the vessel.After the gates are moved to the closed position, the ballastcompartments in the gates are filled with air through the valves 50 soas to provide positive buoyancy to the gates. This causes the gates tolift off the horizontal surfaces 32 of the guides thereby pushing upagainst the bottom of the vessel, bringing the sealing members 88 and 90into contact with the bottom of the vessel around the periphery of thedocking well. This compresses the seal strips against the bottom of thevessel, completely sealing off the docking well from the intrusion ofsea water. The docking well can then be pumped dry by conventional pumps(not shown) to provide a drydock storage area for the mining equipment.I

When the mining equipment is to be lowered to the ocean floor, sea wateris pumped in until the well is partially flooded. Air is then releasedfrom the compartments in the gates, allowing sea water to re-enter theballast compartments in the gates. The combined force of the water inthe well and the negative buoyancy of the gates thus cause the gates todrop down on the rollers 38 on the guide surfaces 32. The amount ofvertical movement of the gates is relatively small and well within thenormal tolerances of the engaging teeth of racks 52 and 54 and gears 56.The seal thus broken, the gates can then be rolled back on the guides tothe open position. Stops are provided at the ends of guides 24 and 26which prevent the gates from being driven too far outwards in theguides. The stops may be provided with suitable sensing means forinterrupting automatically the drive mechanism when the gates move to afully open position.

When the gates are closed mechanical latches 100 are lowered intorecesses 104 in the gates 20 and 22. Lowering and raising of these gatelocking latches is accomplished by a wire line 101 attached to winch 1024 located port and starboard of the well at the main deck. The latches,of course, must be released before the gates are opened.

What is claimed is:

l. A vessel comprising a hull, an open well extending vertically throughthe hull, and gate means for opening and closing the bottom of the well,said means including means for sealing off the bottom of the well whenthe gate means is closed, said means for opening and closing the wellincluding means slidably supporting the gate means for movementhorizontally beneath the hull, the sealing means including meansincreasing the buoyancy of the gate means to cause the gate means torise into flrm sealing engagement with the hull, and means fordecreasing the buoyancy to cause the gate means to fall away from thehull and permit the gate means to be moved horizontally relative to thehull.

2. The apparatus of claim 1 wherein the gate means includes ballastcompartments, said means for increasing the buoyancy of the gate meansincluding means for admitting air into the ballast compartments, andsaid means for decreasing the buoyancy includes means for flooding theballast compartments with water.

3. A surface vessel for raising and lowering mining equipment comprisinga hull having a bottom, a main deck, and a well opening through the hullfrom the main deck through the bottom of the hull, gate means movablysecured to the bottom of the hull, and means moving the gate meansacross the bottom of the well opening between an open position and aclosed position, means for sealing water out of the well when the gatemeans is closed, the gate means being constructed with sealedcompartments, and further including means for pumping air into thecompartments to displace water and increase the buoyancy of the gatemeans, and means for releasing the air and flooding the compartmentswith water to reduce the buoyancy of the gate means.

4. Apparatus of claim 1 wherein the gate means include first and secondgates, guide means extending fore and aft along the bottom of the vesselalong either side of the well, the gates being movable horizontallybetween said guide means, and drive means for moving each of the gatesalong the guide means toward or away from each other to close or openthe well.

5. Apparatus of claim 4 wherein each of the gates includes sealingstrips along the periphery for sealing the gates to the bottom of thehull and sealing the interface between the two gates when they are inthe closed position.

6. Apparatus of claim 5 wherein the margins of the gates overlap thebottom of the hull on either side of the well, the sealing stripsengaging the bottom of the hull when the gates are closed and pumpedwith air.

7. Apparatus of claim 6 wherein the guide means permits movement of thegates over a limited distance toward and away from the bottom of thevessel, whereby flooding of the gates causes them to sink away from thehull and inflating the gates causes them to rise,

pressing the seals against the bottom of the vessel.

1. A vessel comprising a hull, an open well extending vertically throughthe hull, and gate means for opening and closing the bottom of the well,said means including means for sealing off the bottom of the well whenthe gate means is closed, said means for opening and closing the wellincluding means slidably supporting the gate means for movementhorizontally beneath the hull, the sealing means including meansincreasing the buoyancy of the gate means to Cause the gate means torise into firm sealing engagement with the hull, and means fordecreasing the buoyancy to cause the gate means to fall away from thehull and permit the gate means to be moved horizontally relative to thehull.
 2. The apparatus of claim 1 wherein the gate means includesballast compartments, said means for increasing the buoyancy of the gatemeans including means for admitting air into the ballast compartments,and said means for decreasing the buoyancy includes means for floodingthe ballast compartments with water.
 3. A surface vessel for raising andlowering mining equipment comprising a hull having a bottom, a maindeck, and a well opening through the hull from the main deck through thebottom of the hull, gate means movably secured to the bottom of thehull, and means moving the gate means across the bottom of the wellopening between an open position and a closed position, means forsealing water out of the well when the gate means is closed, the gatemeans being constructed with sealed compartments, and further includingmeans for pumping air into the compartments to displace water andincrease the buoyancy of the gate means, and means for releasing the airand flooding the compartments with water to reduce the buoyancy of thegate means.
 4. Apparatus of claim 1 wherein the gate means include firstand second gates, guide means extending fore and aft along the bottom ofthe vessel along either side of the well, the gates being movablehorizontally between said guide means, and drive means for moving eachof the gates along the guide means toward or away from each other toclose or open the well.
 5. Apparatus of claim 4 wherein each of thegates includes sealing strips along the periphery for sealing the gatesto the bottom of the hull and sealing the interface between the twogates when they are in the closed position.
 6. Apparatus of claim 5wherein the margins of the gates overlap the bottom of the hull oneither side of the well, the sealing strips engaging the bottom of thehull when the gates are closed and pumped with air.
 7. Apparatus ofclaim 6 wherein the guide means permits movement of the gates over alimited distance toward and away from the bottom of the vessel, wherebyflooding of the gates causes them to sink away from the hull andinflating the gates causes them to rise, pressing the seals against thebottom of the vessel.